Article conveyor system
An article conveyor system comprising a conveyor device which conveys a conveyance article in accordance with a command to convey the conveyance article to a target position on a workpiece, a visual detection device which has a camera device which is attached to the conveyor device so as to acquire an image which includes both of the conveyance article and the workpiece after conveyance by the conveyor device and analyzes the image acquired by the camera device to detect the respective positions of the conveyance article and the workpiece, and a judgment device which judges if a position of the conveyance article which has been detected by the visual detection device is located within a permission area which is set for the position of the workpiece.
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1. Field of the Invention
The present invention relates to an article conveyor system which is capable of confirming if a conveyance article has been accurately positioned with respect to a workpiece during a conveyance process for conveying the conveyance article toward the workpiece.
2. Description of the Related Art
Article conveyor systems which convey various conveyance articles toward a workpiece have been known from the past. Further, in recent years, article conveyor systems with visual sensors which can visually detect the positions of a conveyance article and workpiece have been spreading. For example, JP2005-11580A proposes a robot system which conveys a conveyance article toward a workpiece, using position information which has been acquired by a visual sensor. More specifically, in the robot system which is described in JP2005-11580A, a visual sensor which is attached to the second hand acquires position information of a cable with a connector which is gripped by the first hand as well as position information of an opposing connector which is placed on a table. The first hand then conveys the cable with the connector toward the opposing connector, using the position information which has been acquired by the visual sensor. In this way, a conveyance article (i.e., cable with a connector) is assembled into a workpiece (i.e., opposing connector).
However, even if a visual sensor is used to acquire accurate position information, a certain extent of conveyance error will unavoidably occur during the conveyance process by the robot in the case where the operational precision of the robot is insufficient. That is, even if a visual sensor is used to acquire accurate position information, it is not possible to guarantee the positioning precision of the conveyance article with respect to the workpiece. Further, in the robot system which is described in JP2005-11580A, in order to confirm if the conveyance article has been accurately positioned with respect to the workpiece, the visual sensor attached to the second hand has to be moved close to the conveyance article and workpiece, and then the visual sensor has to acquire an image including both the conveyance article and workpiece. In this way, in a conventional article conveyor system, a large amount of man hours were required for confirming if a conveyance article has been accurately positioned with respect to a workpiece.
An article conveyor system which is capable of confirming if a conveyance article has been accurately positioned with respect to a workpiece during a conveyance process for conveying the conveyance article toward the workpiece has therefore been sought.
SUMMARY OF INVENTIONAccording to a first aspect of the present invention, there is provided an article conveyor system comprising a conveyor device which conveys a conveyance article in accordance with a command to convey the conveyance article to a target position on a workpiece, a visual detection device which has a camera device which is attached to the conveyor device so as to acquire an image which includes both of the conveyance article after conveyance by the conveyor device and the workpiece, and analyzes the image acquired by the camera device to detect the respective positions of the conveyance article and the workpiece, and a judgment device which judges if a position of the conveyance article detected by the visual detection device is located within a permission area which is set for the position of the workpiece.
According to a second aspect of the present invention, there is provided the article conveyor system in the first aspect, wherein the conveyor device the conveyor device performs a transport process for transporting the conveyance article toward the target position if a position of the conveyance article detected by the visual detection device is not located within the permission area, the visual detection device performs a secondary detection process for detecting a position of the conveyance article after transport by the transport process, the judgment device performs a secondary judgment process for judging if the position of the conveyance article detected in the secondary detection process is located within the permission area, and the article conveyor system further comprising a control system which controls the conveyor device, the visual detection device, and the judgment device so that the transport process, the secondary detection process, and the secondary judgment process are repeatedly performed a predetermined number of times at most.
According to a third aspect of the present invention, there is provided the article conveyor system in the second aspect, wherein the control system sets as a setting value of transport distance in the transport process, a value smaller than a distance between the position of the conveyance article detected by the visual detection device and the target position.
According to a fourth aspect of the present invention, there is provided the article conveyor system in the third aspect, wherein the control system changes the setting value of transport distance so that a ratio of the setting value of transport distance to the distance between the detected position of the conveyance article and the target position becomes smaller as the number of repetitions of the transport process increases.
These and other objects, features, and advantages of the present invention will become clearer with reference to the detailed description of an illustrative embodiment of the present invention which is shown in the attached drawings.
Below, an embodiment of the present invention will be explained in detail with reference to the drawings. In the drawings, similar component elements are assigned similar reference notations. Note that the following explanation does not limit the technical scope of the inventions which are described in the claims or the meaning of terms etc.
Referring to
As shown in
As shown in
As shown in
Next, the visual detection device 3 of the present embodiment will be explained. The visual detection device 3 of the present embodiment includes a camera device 31 which is attached to the hand RH through a predetermined attachment member 311, and an analysis device 32 which analyzes the image acquired by the camera device 31. The camera device 31 of the present embodiment is a digital camera which is provided with a CCD (charge coupled device) image sensor or a CMOS (complementary metal-oxide semiconductor) image sensor or other imaging device. As shown in
In the example of
Next, the judgment device 4 of the present embodiment will be explained. As shown in
The size of the above permission area A, that is, the radius “r” of the fan shape, is determined in consideration of the allowable range of positioning error of the conveyance article W1 with respect to the target position. That is, when the detected position of the representative point P1 of the conveyance article W1 is located inside the permission area A, it is deemed that the positioning error of the conveyance article W1 with respect to the target position is within an allowable range. In this case, the above positioning process is omitted. On the other hand, when the detected position of the representative point P1 of the conveyance article W1 is not located inside the permission area A, the above positioning process is performed by the conveyor device 2, visual detection device 3, and judgment device 4. This point will be explained further later. The result of judgment by the judgment device 4 is transmitted to the above control system 5, and can be displayed on a display device which is installed in the article conveyor system 1 as required. Such a display device is installed in the judgment device 4 or control system 5, for example.
Next, the control system 5 of the present embodiment will be explained. As shown in
In the positioning process of the present embodiment, first, the conveyor device 2 transports the conveyance article W1 toward the target position which is described in the above command. This process will sometimes be referred to below as the “transport process”. The direction in the transport process by which the conveyance article W1 is transported is shown by the arrow A30 in
Next, the operation of the article conveyor system 1 of the present embodiment will be explained in brief.
Next, at step S403, the visual detection device 3 detects the position of the conveyance article W1 after the conveyance process as well as the position of the workpiece W2 (see
More specifically, at step S405, the conveyor device 2 transports the conveyance article W1 to the target position on the workpiece W2. As explained above, in
Referring again to
Note that, when the transport process of the conveyance article W1 (step S405) is repeated two times or more, the setting value “x” of the transport distance is changed so that the ratio α of the setting value “x” of the transport distance with respect to the above distance “d” becomes gradually smaller in accordance with the number of repetitions of the transport process. For example, if the above ratio α in the first transport process is 70%, the setting value “x” of the transport distance is changed so that the ratio α in the second transport process becomes 40%. Further, when the transport process is performed a third time, the setting value “x” of the transport distance is further changed so that the above ratio α becomes smaller than 40%. Normally, as the number of repetitions of the transport process becomes larger, the distance “d” between the detected position (P1) and the target position (P0) of the conveyance article W1 is smaller, and therefore overshoot may easily occur as a result of positioning error of the conveyor device 2. However, if the setting value “x” of the transport distance is suitably changed so that the above ratio α becomes gradually smaller, it is possible to prevent overshoot from occurring in the second round of the transport process onward. As a result, the conveyance article W1 can gradually approach the target position, and therefore it is possible to decrease the number of repetitions of the transport process until the detected position of the conveyance article W1 entering the permission area A. This ensures that the required time of the conveyance and positioning process is shortened.
Referring again to
In the above way, in the article conveyor system 1 of the present embodiment, the respective positions of the conveyance article W1 after conveyance by the conveyor device 2 and workpiece W2 are detected by the visual detection device 3 which is attached to the conveyor device 2, and the position information which is detected by the visual detection device 3 is used as the basis for judging if the conveyance article W1 has been accurately positioned with respect to the workpiece W2. Therefore, according to the article conveyor system 1 of the present embodiment, it becomes possible to easily confirm if a conveyance article W1 has been accurately positioned with respect to a workpiece W2 in a conveyance process for conveying the conveyance article W1 toward a workpiece W2.
EFFECT OF INVENTIONAccording to the first aspect of the present invention, the respective positions of the conveyance article after conveyance by the conveyor device and workpiece are detected by a visual detection device which is attached to the conveyor device, and the position information which the visual detection device detects is used as the basis for judging if the conveyance article is accurately positioned with respect to the workpiece. Therefore, according to the first aspect, it is possible to easily confirm whether the conveyance article is accurately positioned with respect to the workpiece during the conveyance process for conveying the conveyance article toward the workpiece.
According to the second aspect of the present invention, the transport process of the conveyance article is repeated until the position of the conveyance article detected by the visual detection device enters the permission area, and therefore it is possible to position the conveyance article with respect to the processed workpiece with a high precision.
According to the third aspect of the present invention, a value smaller than the distance between the detected position and target position of the conveyance article is set as the transport distance of the conveyance article, and therefore it is possible to prevent the conveyance article from being transported beyond the target position due to the positioning error of the conveyor device.
According to the fourth aspect of the present invention, the setting value of the transport distance is changed so that the ratio of the setting value of the transport distance to the above distance becomes smaller as the number of repetitions of the transport process becomes greater, and therefore even if the transport process of the conveyance article is repeatedly performed, it is possible to prevent conveyance article from being transported beyond the target position due to the positioning error of the conveyor device.
The present invention is not limited to the above-mentioned embodiment and can be modified in various ways within the scope described in the claims. For example, in the above embodiment, as the conveyor device 2, a vertical articulated robot was illustrated, but the conveyor device 2 of the article conveyor system 1 in the present invention can be any mechanical device, including a horizontal articulated robot, orthogonal robot, etc., which can convey a conveyance article W1 to a preset target position. Further, the conveyor device 2 of the article conveyor system 1 in the present invention may be provided with an electromagnetic attraction type or servo drive type of hand RH instead of the vacuum suction type hand RH which is illustrated in the above embodiment. Further, the structures, functions, etc. of the various apparatuses of the article conveyor system 1 which is described in the above embodiments are only examples. Various structures, functions, etc. can be employed for achieving the effects of the present invention. Dimensions, shapes, etc., of the conveyance article W1 and workpiece W2 described in the above embodiments are only examples. Various dimensions, shapes, etc. can be employed for the conveyance article W1 and workpiece W2.
Claims
1. An article conveyor system comprising:
- a conveyor device which conveys a conveyance article in accordance with a command to convey said conveyance article to a target position on a workpiece,
- a visual detection device which has a camera device which is attached to said conveyor device so as to acquire an image which includes both of said conveyance article after conveyance by said conveyor device and said workpiece, and analyzes said image acquired by said camera device to detect the respective positions of said conveyance article and said workpiece, and
- a judgment device which judges if an edge of said conveyance article detected by said visual detection device is located within a permission area which is set within a region on said workpiece, the region is an area on said workpiece located within a predetermined radius measured from an edge of said workpiece, wherein
- said conveyor device performs a transport process for transporting the edge of said conveyance article toward said target position if an edge of said conveyance article detected by said visual detection device is not located within said permission area,
- said visual detection device performs a secondary detection process for detecting the edge of said conveyance article after transport by said transport process,
- said judgment device performs a secondary judgment process for judging if the edge of said conveyance article detected in said secondary detection process is located within said permission area, wherein
- said article conveyor system further comprising a control system which controls said conveyor device, said visual detection device, and said judgment device so that said transport process, said secondary detection process, and said secondary judgment process are repeatedly performed a predetermined number of times at most, and wherein
- said control system sets as a setting value of transport distance in said transport process, a value smaller than a distance between the edge of said conveyance article detected by said visual detection device and said target position.
2. The article conveyor system according to claim 1, wherein
- said control system changes said setting value of transport distance so that a ratio of said setting value of transport distance to said distance becomes smaller as the number of repetitions of said transport process increases.
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Type: Grant
Filed: Aug 31, 2015
Date of Patent: May 30, 2017
Patent Publication Number: 20160068352
Assignee: Fanuc Corporation (Yamanashi)
Inventor: Masaru Oda (Yamanashi)
Primary Examiner: Thomas Randazzo
Application Number: 14/840,238
International Classification: G06T 7/70 (20170101); G06T 7/11 (20170101); G06T 7/13 (20170101); G05D 3/12 (20060101); B25J 9/16 (20060101); B65G 43/08 (20060101);